Hi peeps. I could use some help in upgrading my pc. First off what's the best cpu to use with regards to cores??? I really can't decide between a dual or quad setup. I have an Nvidia Nforce 620i SLI motherboard so it's either an Intel core 2 duo or quad but it will run the Extreme cpu's too. I usually buy AMD but the motherboard found it's way into my posession after parting with a substantial amount of cash. lolhttp://www.nvidia.com/page/nforce_600i_tech_specs.html

Next up is the graphics card. Now i prefer Nvidia cards but there's a few other's i've looked at. Atm i'm using an ATI radeon HD4650 which is a pretty good card for the games i play but not quite upto the newer games.
Since my motherboard has multiple PCI-e slots i can easily add a second card at a later date if needed. Just 2 things it must have. First is an HDMI slot and second it must cope with HD resolution gaming.

I know there's some tech heads out there. I appreciate all the help i can get finding the right parts at reasonable prices. There's so much out there right now i really can't decide. The case is the only thing i knew i wanted which is an NZXT Lexa s with red lighting.

Isn't that motherboard ~5 years old?
I really don't think you should put any money into it at this point. Intel made a substantial tech leap in meantime and they use new sockets now. You might be able to reuse the case, but otherwise I think you're gonna need a fresh start.

I'd recommend a book, Building the Perfect PC by the Thompson. It's full of good advice and will prevent you from accidentally putting a bottleneck in your system, or worse, buying something that doesn't fit.

If you don't want to think about it that much, then here's a good starting point to choose some nice up-to-date components for not too much $:Tom's Hardware System Builder -- Gaming PC
I wouldn't recommend deviating from that build though unless you read the book first.

I find that computer parts and what not all depends on what people want to spend. I have helped out alot of customers in the past who wanted the "cheap but good" and it was really hard to meet that requirement. But now adays its easier to do.

If you want to do a total upgrade, and want to keep it easy on the wallet, then I would recommend AMD. I am currently spec'ing out an upgrade for myself, and from what I've heard from friends, the AMD processors are the best bang for the buck right now. I'm not sure where you reside, but in Canada, you can get a HexCore for approx $150. I'm still a fan of the Intel processors, but as I get older, I find my wallet doesnt hold as much money as it used to when i didnt have rent, car payments, and the biggest money drain...a girlfriend lol..

In terms of motherboards and if you go with AMD, if you still want to stick with Nvidia graphics card, I would suggest you stear clear of Mobo's that have on-board video. If I can recall, all AMD mobo's with on-board graphics use a ATI on-board chipset. When combined with an Nvidia graphics card, it can cause more problems then you like. They can be ironed out, but I personally like to avoid them at all cost haha.

Memory wise, once you pic the mobo that you want, i would strongly suggest checking out the manufactures site to see what ram they have tested and certified with that model. With alot of the mainstream boards (Asus, Gigabit ect..) i find that OCZ, Corsair, Kingston are sure bets. I personally run Corsair XMS.

Lastly, I would make sure, if you don't already, have a decent wattage Power Supply. I usually recommend at least 600Watts. This is my personal preference in instances of future upgrades, such as second video card, more hard drives blah blah blah

Oh and if you want to get real fancy, might I suggest a Solid State Drive. All I have to say is F-ing amazing. Load times are crazy and just seem to make everything so....flawless... lol

Yes it's an older model motherboard but this one has never been used. It'll still keep up with the newer boards. I've seen these overclocked silly amounts so even if it is the older model it's still as good or in some cases better than what's available now.

I already have a Corsair 750w psu, a friend recommended it.

I was looking at memory earlier and the guy says the Corsair memory is one of the best. I'd be looking at about 4gb for my price range.

What i need to know is, is it worth spending the extra cash and going for a quad core processor or shall i stick to a dual core??? From what i've been told the more cores you have the smaller they get. The setup i have now is a single core 4ghz, my old pc had a dual core but it was only 3ghz so i'm guessing a quad will be smaller still.

Yes it's an older model motherboard but this one has never been used. It'll still keep up with the newer boards. I've seen these overclocked silly amounts so even if it is the older model it's still as good or in some cases better than what's available now.

I already have a Corsair 750w psu, a friend recommended it.

I was looking at memory earlier and the guy says the Corsair memory is one of the best. I'd be looking at about 4gb for my price range.

What i need to know is, is it worth spending the extra cash and going for a quad core processor or shall i stick to a dual core??? From what i've been told the more cores you have the smaller they get. The setup i have now is a single core 4ghz, my old pc had a dual core but it was only 3ghz so i'm guessing a quad will be smaller still.

Umm, better than a z68? No. No its not. Hell, my build is 2 years old and its ok but not kicking A's and taking names. And I'm running a i5 650(dual core 4 threads) oc'ed to 4.00ghz 8 gigs of corsair memory DDR3 1600 on a P55-ud4p gigabyte board, and a pair of hd 5770 crossfired. All powered by a cooler master silent pro 850w. You may want to rethink that again.

for this game you don't need a quad. a dual works fine. but a good dual or a sub par quad would be the best bet. for my processor and graphics cards I have the highest 3d mark 11 score. But my cpu is a bottleneck and my cards are on the tail end of useful (highest game settings) it can play with everything on but I want better fps.

My memory, psu and graphics cards will carry over into my next build until I buy a better graphics card. I'm waiting for Ivy bridge.

Oh, I should also mention it's a good idea to use a power transformer that has about twice the capacity that you actually use. The reason is that those things are tweaked to deliver maximum efficiency at 50%.

So, if you sit down and figure that your computer would max out at 250W, then a 500W transformer should be all you need. If you go overboard and get a 1000W transformer, then your'll end up drawing 300W to power it instead of 250W just from the inefficiency of it.

Sticking with that board if you ever tried to put two video cards in you're gonna need a pair of nvideas to get the most out of it. I built a new one last summer to bet better performance here. Spent 400 just on the core components and transferred some others from the old build. Frame rates dip to 45fps and average between 55-60.